Electrical switching device



Sept. 19, 1933. BALOUN 1,927,512

,ELECTRICAL SWITCHING DEVICE Filed April 15, 1951 Patented Sept. 19, 1933 ELECTRICAL SWITCHING nsvrcr:

Kurt Baloun, Berlin, Germany, assignor to Siemens &- Halske Aktiengesellschatt, Wernerwerk, Siemcnsstadt, near Berlin, Germany Application April 15, 1931, Serial No. 530,334, and in Germany July 13, 1930 dClaims. (Cl. 175-820) The present invention relates in general to arrangements for introducing an element of time into the operation of electrical switching devices and is concerned primarily with circuit arrangements for the retardation of the switching operations of such devices.

Arrangements are already known for the retardation of switching operations in which the influence of heat on metal is utilized, such as in the case of, for example, thermo relays. The object of the present invention is to take advantage of the fact, in order to efiect a retardation of switching operations, that the resistance in conductors increases when heat in applied; and this is achieved by connecting up a resistance having a high temperature resistance coeificient in the circuit of the switching means which effect the switching operations, whereby this resistance, owing to the influence of a source of heat, grad- 2 ually causes the current for the switching means to be reduced or increased by alteration of its electrical resistance. 1

The arrangement, according to the invention, can be used with great advantage for slow interrupters used in telephone systems as shown by the embodiment in Fig. 2.

An embodiment of the subject of the invention is shown in the drawing. Fig. 1 shows an arrangement for deenergizing a relay after a predetermined interval. Fig. 2 shows an interrupter or impulse generator. Only the switching elements necessary for a complete understanding of the invention have been shown. The invention 'is not limited to the embodiments hereindisclosed.

A retardation arrangement for relay C is shown in Fig. 1. In this circuit the relay releases with slow action accounted for by the winding A, located in the circuit for relay C. Winding A consists of a conducting lead with the highest possible temperature resistance coeflicient, and is arranged so that it can be heated by the heating winding B, whereby the resistance of winding A is increased.

When the key T in this arrangement is closed, theiollowing circuit is completed: Positive pole of battery, key T, winding of relay C, winding A,

negative pole of battery; and, further, a circuit is completed for the heating coil B, which is thermally connected to A.v In the described circuit the relay C is energized whereupon it opens its contact 10 and closes contact 20. The heating element B warms up and transmits heat to the winding A, whichwarms up also. The resistance otthis eflectisincreased duetotheheating winding, with the result that, if the correct resistance has been selected, relay C releases with slow action due to the gradual warming up. Contact 2c is thereby opened and contact 10 closed.

Fig. 2 shows the use of the arrangement according to the invention in connection with a slow interrupter. When in this circilit arrangement a contact San, dependent upon any relay, is closed, the relay C1, which is connected up in series with a resistance A1, is energized in the following circuit. Positive pole of battery, contact Ban, winding of relay C1, resistance A1, negative pole of battery. The relay C1 closes its contacts 401 and 301. Over contact 401 a heating coil B1 is connected up which warms up grad ually and heats the resistance A1 by degrees. When the resistance in winding A1 has risen to a certain value the relay C1 again releases. The inter-action continues as long as 5an is closed so that a circuit in which various switching devices can be located, (i. e. stepping switches) is opened and closed at definite periods of time by the contact 301.

What is claimed is:

1. A circuit controlling device comprising two conductors connected respectively to the two poles of a current generator, a relay connected across said two conductors, a resistance having a positive temperature resistance coeflicient connected in series with said relay, and a heating element connected across said conductors for regulating the value of said resistance.

2. A circuit controlling device comprising two conductors, means for connecting the conductors to the two poles of a current generator, a relay and a variable resistance connected across said two conductors, a heating element for regulating the value of said resistance, and circuit connections controlled by said relay for connecting and disconnecting said heating element and said two conductors to effect the alternate energization and deenergization of the relay as long as the conductors remain connected to the generator. 3. In a circuit controlling device, two conductors, a relay and a temperature regulated variable resistance connected across said conductors, a source of current and means for connecting the same across said conductors to operate said relay provided said resistanceis at normal temperature, a heating element for raising the temperature of said resistance to a point at which said relay deenergizes, and contacts controlled by said relay for' connecting said heating element across said conductors.

4. The combination comprising a closed elecno said relay, and means controlled by the relay on deenergizing for disabling'said heating element thereby permitting said resistance LO return to normal temperature and permit the reenergization of the relay.

KURT BALOUN. 

